Later he moved up to the heavyweight division and joined Koshinaka Shirō to form the "Han-Senshukai Dōmei" (Alliance against the Wrestlers Association), which was renamed Heisei Ishingun in 1993.

Around this time, Kobayashi had two colorectal cancer surgeries. In 1999, he had surgery to battle liver cancer. The Heisei Ishingun dissolved in the same year, and Kobayashi had his last match on 2000/4/21 against Jūshin Thunder Liger. Sayama was one of the guests for the retirement ceremony, and Misawa also sent a message.

Since the retirement, Kobayashi has remained involved in puroresu, currently as caretaker of the New Japan Dōjō. He occasionally wrestles in legends matches.